The removal of toxic gases from airstreams is of great importance for respiratory protection and gas filtration.  We report here on two distinct approaches in developing a single material with the ability to remove a broad spectrum of toxic chemicals including ammonia (NH3), sulfur dioxide (SO2), nitrogen dioxide (NO2), and cyanogen chloride (ClCN).  In the first approach composites were made from the powders of Cu-BTC, UiO-66-NH2, and ZnO.  These materials have been shown to be able to target ammonia, sulfur dioxide, and cyanogen chloride, respectively.  It was found that within the composites there were no deleterious effects and the removal capacity of each composite was approximately a weighted average of each component for each TIC studied.  Furthermore, synergistic effects were found between the MOFs and ZnO as the hydrophilic MOFs could supply water that is utilized by ZnO causing a significant increase in the capacity for sulfur dioxide.  In the second approach UiO-66 was post-synthetically modified with oxalic acid (UiO-66-ox).  UiO-66 already has significant removal capacity for ammonia and cyanogen chloride.  UiO-66-ox showed a dramatic increase in capacity for sulfur dioxide and nitrogen dioxide, without a decrease in capacity for ammonia or cyanogen chloride.  The carboxylate group bound to the MOF has the ability to oxidize sulfur dioxide and nitrogen dioxide, an approach that can be applied to the removal of other toxic chemicals.  Both of the approaches presented here should be considered when engineering materials for toxic gas filtration.

Strategies for the broad spectrum removal of toxic gases by metal-organic frameworks

248th National Meeting (2014)

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